RAM is absolutely central in a computer, nothing goes anywhere but via RAM.
All input or output devices (keyboard/mouse, scanner, printer, monitor, ...)
all storage devices, hard disk, CD, floppy disk, digital camera, memory stick, ...
all first get or move their information to RAM before it goes anywhere else
under control of a program in the RAM containing instructions to the CPU
(Central Processing Unit), that controls the whole computer.
So RAM can be thought of as central to a computer.
Some might say the CPU is the most important component,
maybe it is, but it is not central, the RAM is.
Before 1960 RAM was in various forms: William's Tube; Mercury Delay Line; ...
but in the early 1950s work was underway developing "core storage".
For the next 20 years RAM was core storage.
Then came silicon and solid logic technology,
then large scale integration (LSI), the very LSI (VLSI),
until now 2004, they have run out of superlatives.
But this is about core storage which 1MB in 1967 weighed 5 tonnes,
used 50KW of electricity, cost half a million pounds then, and in 2004
can be bought for 10p.
Core storage was of several types: two, three or four wire;
depending on the number of wires that threaded each core.
The most successful was 3 Wire Core Storage.
Assuming you have read and understood that we can look at the exhibits in the museum.
We start with the System 360 core storage and then look at earlier and later core storage.